# Quick Lime, Slaked Lime & Lye

Discussion in 'Chemistry' started by Orleander, Jan 24, 2009.

1. ### OrleanderOH JOY!!!!Valued Senior Member

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what is the difference between these besides the chemical properties?
And why do they put it in graves?

3. ### TrippyALEA IACTA ESTStaff Member

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Quick lime = Calcium Oxide $CaO$
Slaked Lime = Calcium Hydroxide $Ca(OH)_2$
Lye = Sodium Hydroxide $NaOH$

Quicklime used to be used for stage lighting.
Lye gets used for curing some foods (eg Pretzels), and in soap.
Slaked lime in solution can react violently with acids and metals, and gets used in conjunction with alkaloids to enhace their uptake and metabloism. Slaked lime can also improve the nutritional value of maze and corn - Hominy is corn (I think) soaked and cooked in a solution of slaked lime.

All three have substantial anti microbial properties (as I understand it) so I imagine their use in graves has something to do with that (as opposed to ther other uses).

5. ### KilljoyPropelling The Farce!!Valued Senior Member

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Quicklime hastens decomposition.

Don't recall its use in the modern-day graves I've seen people lowered into, but for mass graves such as those of nazi holocaust victims, one presumes it was to dispose of "evidence" ASAP.

The anti-microbial properties mentioned by Trippy might explain it's use in "Pauper's graves", where the body was not even placed in a wooden coffin, such as the graves of smallpox victims described here.
Not sure if the nature of how the disease was spread was understood then, though. They might have simply been trying to dispoe of the bodies more quickly.

7. ### Captain KremmenAll aboard, me Hearties!Valued Senior Member

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Why do you want to know?
Who are you thinking of killing?

8. ### OrleanderOH JOY!!!!Valued Senior Member

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is it naturally occurring or does it have to be made?

If someone screwed up and put lye in the grave instead of quicklime, would the body be preserved instead of decomposed?

Does the lime help in stopping the spread of diseases?

9. ### TrippyALEA IACTA ESTStaff Member

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It can be naturally occurring, but is, AFAIK, rare.

No, Lye is caustic and corrosive.

10. ### Captain KremmenAll aboard, me Hearties!Valued Senior Member

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It depends on weight.
I mean the body.

11. ### OrleanderOH JOY!!!!Valued Senior Member

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but don't they use Lye on green olives and to make hominy?

12. ### OrleanderOH JOY!!!!Valued Senior Member

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I would never ever have a need for lye or lime.
We have a fire pit

13. ### TrippyALEA IACTA ESTStaff Member

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And Pretzels, yup.

14. ### OrleanderOH JOY!!!!Valued Senior Member

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then how is lye corrosive if we eat it? What is it corroding on a pretzel?

15. ### TrippyALEA IACTA ESTStaff Member

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Because Lye is Caustic Soda.
I've never understood why Causic Soda gets used in cooking.

Sodium Hydroxide pellets are nasty stuff, you can buy them from your hardware store.

http://msds.chem.ox.ac.uk/SO/sodium_hydroxide.html

Typically, I imagine that during the cooking process, the Lye would react with other things in the food before you ingested it.

But the simple fact of the matter is that Lye is a strong base (one of the strongest) and as such is highly corrosive.

16. ### TrippyALEA IACTA ESTStaff Member

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As a side note - when I went through highschool, it was long enough ago that when we did titrations, we operated pippettes by the liquid into them.

I once misjudged it, and wound up with a mouthfull of dilute Sodium hydroxide solution - not an experience I'll soon forget.

17. ### Walter L. WagnerCosmic Truth SeekerValued Senior Member

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Being in the limelight was being illuminated for your photograph with quicklime lighting.

18. ### Captain KremmenAll aboard, me Hearties!Valued Senior Member

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Lye or Lye water in Asian cooking is used as both a preservative and it breaks down hard fibers, as the lye opens up the fibers to allow them to cook, and you do not cook thing in lye, but soak them or treat them to soften them before cooking and you rinse off the the lye.

At no point do you actually ingest it.

19. ### TrippyALEA IACTA ESTStaff Member

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All I know about the use of Lye in cooking is that it's used for curing pretzels, i've never actually prepared Pretzels myself, nore have I specifically looked into pretzel recipes, however I imagine that even in the example you give that some of the Lye soaks into the food. I suppose the key point that's worth noting here is the quantities of Lye involved are pretty minimal, and like most toxins its effects are dose dependent.

In other words - curing pretzels might require say 5g in a 1kg batch (NOTE: I have never looked into preparing pretzels, and have no idea what the actual dosing rate is, don't take this figure as gossple) at this level, it might be sufficient to have the required preservative effects, but sufficiently dilute that it affects the taste slightly and little else (probably a better answer to your previous post).

20. ### OrleanderOH JOY!!!!Valued Senior Member

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why? Why soak food in lye? Is it for taste or does it help you absorb nutrients better?

And why throw lime on bodies and not lye?

21. ### TrippyALEA IACTA ESTStaff Member

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I imagine it has something to do with it's corrosive properties, and the fact that it's corrosive properties also affect tough husks and fibers, softening them before they're ingested to make whatever's inside the tough husk more accessable to the stomach (and human body).

Think of it as partially digesting the food before you consume it.

Pass. I'm neither a grave digger, nor a mortician.

Although, if I were to guess, I would have to guess that one reason might be that lime is more easily stored then Lye is, it also seems liek it might be less toxic or problematic to handle (and for living relatives to be around - funerals and all that) then lye is.

22. ### CharonZRegistered Senior Member

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Usually they are dunked half a minute in roughly 1M NaOH. This concentation is not enough to harm your skin for example, and the final concentration (the residue on the pretzels = weird pronounciation, actually) is far lower even.

23. ### kevinalmRegistered Senior Member

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One of the main reasons to use lye in cooking is to assist in rehydrating dried foods. The scandinavian dried fish "lutefisk" for example, which translates something like soaked fish. The dried fish is placed in a dilute NaOH solution for several days. The lye assists in hydrating the fish and also prevents spoilage. Then several changes of fresh water are used over a day or so to flush out excess lye and "firm up" the fish to the desired texture.

Lye was also used in the making of 'hog slop'. Ground grain and water was put in a metal barrel. Then a pound or two of lye per hundred gallon was added which heated the water and soaked/cooked the grain. (not sure of the exact amount, Dad told me about grandpa doing it, and hog producers in the States haven't used 'hog slop' in like 75 years or so)

I'll take a guess as to why quicklime is used in mass graves. If anything it is more corrosive than lye. And its final state in the soil is calcium carbonate, which would tend to cement the soil together and hold in odors. Even cadaver dogs might have a hard time finding the gravesite.

Last edited: Jan 28, 2009